In the remote manipulator art, numerous types of "hand" units have been devised for grasping an object to move that object from one location to another, to perform some operational task, etc. Most of these hand units (commonly called "end effectors") are simply a pair of fingers or tongs that move in a parallel relationship toward or away from each other. Typically, these tongs that are to grasp the object have a resilient surface to improve grasping friction, and some units provide for pressure-related feedback to insure proper grasping force.
In order to grasp an object using these devices of the prior art, the device must be seen either directly or through the use of video equipment so that a proper grasping location on the object is utilized to minimize inadvertent disengagement. For example, generally spherical objects must be grasped at a major diameter, necked-type objects grasped at the neck, etc. Where objects of a particular configuration are to be grasped routinely, tong units of a configuration matching the object can be used. Highly irregularly shaped objects, particularly those with sloped surfaces, are grasped with only great difficulty, perhaps after several attempts. Further, if the object is unknown in configuration when grasped, it must be directly or indirectly viewed to ascertain a proper location for grasping the same.
There are applications for remotely operated grasping devices where the object is only partially seen or even cannot be seen by conventional means. For example, in underwater exploration, the murky waters usually encountered prevent any viewing. Also, light distortion hampers exact positioning of the device. Thus, it becomes important that the object be grasped without such exact positioning.
Numerous special configurations of grasping means have been developed, some of which are designed to grasp objects of unusual exterior shape. One such device is described in U.S. Pat. No. 4,572,564, issued to T. M. Cipolla on Feb. 25, 1986. Other typical devices are described in U.S. Pat. No. 4,047,709, issued to B. S. J. Thyberg, et al. on Sept. 13, 1977; U.S. Pat. No. 4,632,444 issued to M. R. Martinez, et al., on Dec. 30, 1986; U.S. Pat. No. 4,088,312, issued to NASA on May 9, 1978; and U.S. Pat. No. 4,609,220, issued to P. B. Scott on Sept. 2, 1986. None of these devices are adapted for convenient use as a hand of a remotely operated grasping device.
The most pertinent of the prior art appears to be the patent to Cipolla ('564). The device shown therein has a pair of jaws that can be moved toward or away from each other. Each of the jaws has a plurality of "fingers" projecting from confronting surfaces, with these fingers being biased outwardly to an extreme deployed position. When the jaws are moved toward each other, any object positioned between the sets of fingers causes the fingers to be forced back into the jaws. This is a "passive" movement of the fingers. The position of the fingers, at maximum movement, is "locked" such that the jaws can be opened without the fingers returning to the extended position until intentionally released.
Another of the cited patents, that to Scott ('220), utilizes a plurality of finger units that depend from two jaws, with the jaws being movable toward and away from each other. As in the '564 reference, the fingers are normally biased to their fullest point of deployment and are moved only by the object that they encounter during movement of the jaws; i.e., again passive movement of the fingers. Due to the configuration of the finger units, many configurations of objects cannot be grasped by the device of this reference.
Accordingly, it is a principal object of the present invention to provide a hand unit for a remotely operated device, said hand providing a capability to grasp a surface having either a regular or irregular configuration.
It is another object of the invention to provide a device which can grasp an object and then reorient the object into a selected new orientation.
A further object of the present invention is to provide a grasping unit to be utilized as an end effector of robotic equipment wherein a housing is provided that will store a plurality of finger units until a selected portion thereof are intentionally deployed from the housing whereby a distal end of at least a portion of the deployed fingers grasp the surface of an object for the intended purpose.
Also, it is an object of the present invention to provide a housing of fixed configuration that defines a working volume that will accept at least a portion of an object to be grasped, the housing having a plurality of finger units that can be deployed from a stored position within the housing into the working volume whereby the distal end of at least some of the fingers contact the surface of the object to grasp the same.
These and other objects of the present invention will become apparent upon a consideration of the drawings referred to hereinafter in combination with the detailed description thereof.